Method for monitoring a laser soldering process, and laser soldering system using a spectroscope device

Abstract

A laser soldering system and a method for monitoring a laser soldering process by means of a monitoring device of the laser soldering system, wherein a solder ball is dispensed onto a solderable surface of a substrate by means of a solder ball feeding device of the laser soldering system, wherein the solder ball is at least partially melted by means of a laser device of the laser soldering system, wherein, during the laser soldering process, a light signal is formed which is detected by means of an optical detection unit of the monitoring device, wherein the light signal is dispersed into a spectrum of the light signal by means of a spectroscope device of the monitoring device, wherein the spectrum is analyzed by means of a processing device of the monitoring device, and it is identified on the basis of a composition of the spectrum whether or not a burning of the substrate has occurred during the laser soldering process.

The invention claimed is: 
     
         1 . A method for monitoring a laser soldering process by means of a monitoring device of a laser soldering system, the method comprising the steps of,
 dispensing a solder ball onto a solderable surface of a substrate with a solder ball feeder of the laser soldering system;   at least partially melting the solder ball with a laser device of the laser soldering system;   forming a light signal during the laser soldering process and detecting the light signal with an optical detection unit of the monitoring device;   dispersing the light signal into a spectrum of the light signal with a spectroscope device of the monitoring device;   analyzing the spectrum with a processing device of the monitoring device, and on the basis of a composition of the spectrum, identifying that a burning of the substrate has occurred during the laser soldering process by identifying that the spectrum comprises a substrate-dependent burning portion; and   differentiating between a substrate-independent normal portion and the substrate-dependent burning portion with the processing device.   
     
     
         2 . The method according to  claim 1 , further comprising the step of determining a material or a material composition of the substrate based on a composition of the substrate-dependent burning portion. 
     
     
         3 . The method according to  claim 2 , wherein the determination is carried out by comparing characteristic parameters of the substrate-dependent burning portion with characteristic parameters which are stored in a database of the processing device and which spectroscopically describe a plurality of different materials or material compositions of substrates. 
     
     
         4 . The method according to  claim 1 , further comprising the step of outputting whether or not a burning of the substrate has occurred during the laser soldering process with the processing device. 
     
     
         5 . The method according to  claim 1 , further comprising the step of stopping an operation of the laser soldering system when a burning of the substrate is identified during the laser soldering process. 
     
     
         6 . The method according to  claim 1 , wherein the light signal is formed due to at least one of the melting of the solder ball and the burning occurring during the laser soldering process. 
     
     
         7 . A laser soldering system, comprising a solder ball feeder for dispensing a solder ball onto a solderable surface of a substrate and a laser device for at least partially melting the solder ball, wherein the laser soldering system comprises a monitoring device for monitoring a laser soldering process, wherein the monitoring device has an optical detection unit for detecting a light signal which is formed during the laser soldering process and a spectroscope device for dispersing the light signal into a spectrum of the light signal, wherein the monitoring device has a processing device by means of which the spectrum is capable of being analyzed to identify on the basis of a composition of the spectrum whether or not a burning of the substrate has occurred during the laser soldering process, and wherein the spectrum comprises at least one substrate-independent normal portion and, in the case of a burning of the substrate occurring during the laser soldering process, furthermore comprises a substrate-dependent burning portion, wherein a differentiation is made between the substrate-independent normal portion and the substrate-dependent burning portion by means of the processing device. 
     
     
         8 . The laser soldering system according to  claim 7 , wherein the optical detection unit comprises at least one convergent lens. 
     
     
         9 . The laser soldering system according to  claim 7 , wherein the laser soldering system comprises a glass fiber assembly by means of which the light signal is transmittable from the optical detection unit to the spectroscope device. 
     
     
         10 . The laser soldering system according to  claim 7 , wherein the processing device comprises a database in which a plurality of characteristic parameters which spectroscopically describe different materials or material compositions of substrates is capable of being stored.